MSR Reactor 1.0L Stove System

I just got from a 2 week backpacking trip where I field tested an MSR Reactor 1.0 Liter Stove System. While the MSR Reactor is not the lightest weight backpacking stove available or the most flexible (because it can’t truly simmer), it is:

Completely windproof

Lights without a big gas flame up

Is 40% more efficient than most other pot & canister stove combinations

You can drink tea and cook very simple one pot meals in it

These were the primary reasons I brought it with me when I backpacked 200+ miles across Scotland in 13 days: Scotland is always very wet and windy, I needed a stove that was safe enough to cook with under a pyramid tarp (I’ll cover the carbon monoxide issue danger below), I needed an efficient stove in case I couldn’t resupply fuel canisters easily, and I don’t like to carry an extra cup or plate when I can eat and drink out of a pot.

It’s also nice that the MSR Reactor Stove System boils water faster than any other stove on the planet (2 cups in 1:30 to 1:45). But that was really a secondary benefit as far as I was concerned, although it never ceased to amaze my companions, especially when I made a brew out in the open on a windy day!

Eating a simple ramen dinner from the 1.0 Liter Reactor Pot

The Reactor Stove System

If you are unfamiliar with the Reactor, it’s important to understand that it is a complete isobutane gas powered stove system that comes with an unusual looking stove, an extremely efficient 1.0 Liter pot with heat exchange fins and a built-in wind screen, a plastic pot lid and a collapsible metal handle. While you can use the pot with another stove, the stove has a special shape that will only work with 1.0 liter, 1.7 liter, or 2.5 liter Reactor Pots. If you already own a Reactor system you can buy the different sized pots separately.

The stove part of the Reactor is compatible with any size or make Isobutane fuel canister as long as it mates to the stove using screw-on threads. This is normally not an issue in the US, but it can be a showstopper in the UK and Europe if you buy fuel canisters with a bayonet style connector like the ones from Camping Gaz.

MSR Reactor Stove Head

The Reactor Stove

The Reactor Stove convex heating surface that’s shaped like the surface of the sun instead of a gas burner like most other isobutance canister stoves. When lit, the stove fits into a recessed cavity on the bottom of the specially-designed Reactor pots at an optimal distance for efficient heat transfer and elminates any need for a separate windscreen. It’s really rather brilliant.

There’s also no open flame jumping off the surface the stove’s “radiant” heating element which makes it much safer to use under many tarp shelters that typically have a lower ceiling than many higher walled tents. It’s important not to light any stove in a closed shelter without adequate ventilation because the resulting carbon monoxide can cause brain damage or suffocate you (BEWARE of LETHAL DANGER!) That said, the reality is that people have to cook inside shelters in bad weather when they go backpacking and it’s not something you can avoid if it’s pissing down rain outside or you need hot food and drink. If you do it though, make sure you have a good breeze blowing through your shelter.

To light the Reactor stove, you need to open the gas valve and use a match or firesteel to ignite the fuel vapor. Unlike a JetBoil, there’s no built-in piezo ignition provided. I only use a firesteel because it always works, even in damp conditions, and I feel that it’s safer than an open flame under a tarp or tent fly. If you’re quick about it, there’s also very little flame up above the Reactor stove surface, making it safer to use in close quarters if you want to avoid burning down your tent or shelter around you (I doubt MSR’s lawyers will agree…purely because they fear the liability consequences of claiming it.)

Although you can regulate how much gas the stove gets, the Reactor is primarily designed for boiling water or melting snow and is perfect for quickly boiling water if you’re eating a commercial Mountainhouse style meal in a bag.

Simmering is difficult because the Reactor stove goes out when you try to turn the gas down low. The problem is not the stove per se, but the efficiency in which the heat of the stove is transferred to the pot and because turning down the gas does not result in a corresponding drop in the temperature of the liquid inside like other stove/pot combinations.

1.0 Liter Pot Bottom and Heat Exchange Fins

Why is the pot so much more efficient than a regular backpacking pot? It all boils (har har) down to the way the pot is made, with an integrated wind screen at the bottom, which acts as a double wall around the base of the inner pot. Hot air from the stove is channeled into the recess at the bottom of the pot and up its sides by the heat exchange fins welded to the pot bottom. The hot air contained within the wind screen helps maximize the surface area that can warm the liquid in the pot and continues to heat the contents of the pot even after the stove is turned off!

Knowing this, you can immitate the effect of a simmer by bringing the water in the pot to a rapid boil, adding your ingredients to it, turning off the stove and then letting the contents sit a moment. The hot air surrounding the pot, the hot liquid, and the hot metal of the pot will continue to “cook” the ingredients because the heat exchange fins and integrated wind screen retain heat so well. If needed you can bring the liquid in the pot quickly back to a boil by relighting the stove and then turning it back off to rest and cook the ingredients some more. In essence, the pot is acting like a pot cozy.

This makes it possible to make very simple recipes in the anodized Reactor pots if all you need to do is to rehydrate homemade freezer bag meals, cook ramen noodles, or heat up soups. For example, to cook ramen noodles, I typically add about 0.60-0.70 liters of unsantized water from a stream, turning the stove off when it reaches a roiling boil. I add the noodles, a packet of miso, and 1 ounce of olive oil, then mix them together and let them sit for a minute. Then I turn the stove back on, bring the hot liquid back to a boil, and turn it off to let it “cook” for another minute or two. That’s all it takes to make ramen noodles.

The handle of the 1.0 Liter pot reverses and locks down the lid

Packability

The handle of the 1.0 Reactor pot flips over itself and locks down over the top of the pot making it possible to store the stove head, a small gas canister, and a small camping towel (included) as a single self contained unit for ease of packing. That’s the theory anyway, because the handle slips out of its ball lock easily during transport. In practice, I found it best to store the stove upside down in my backpack to hold the compenents together using gravity. There’s got be a better way to secure the lid so it doesn’t pop off so easily.

Recommendation

At 14.4 ounces, the 1.0L Reactor Stove Stsyem is not the lightest isobutane gas stove available and it’s difficult to cook complex meals with it beyond soupy backpacking fare or easy 1 pot meals. However, it has a lot going for it in terms of fuel efficiency and windproofness for remote locations and adverse conditions where reliability, fuel efficiency, cooking speed, and a well controlled flame are paramount concerns. I really enjoyed testing it on a tough 13 day backpacking trip in challenging spring conditions and I plan to use it for other similarly challenging adventures in the future.

25 comments

Nice review. Could you please say how much gaz this stove usually uses to boil 1L or may be I can tell me how many liters did you boil during your trip and how many gas did you used for it. I’m interesting in field experience rather that manufacturer’s data. I’d like compare it with my Primus Eta Solo.

Not to knock your results, but I view all stove efficiency measurements with a grain of salt. What’s 33% outside of the tent mean? Was there wind? What was the starting temp of the water? What was your altitude? How much gas was vented before you started each burn, and so on.

I make sure I have enough extra fuel to make it through a trip even if that means eating a cold meal or two to make sure that I conserve my fuel all the way through.

That’s why I go on and on about the functional merits of this stove system in this review independent of the boil time metrics. It’s wind proof and safer than an open flame. It’s also a fast boiler, but that’s a given. I don’t really care how much faster to be honest, but it’s fun to show off.

I too have used this stove and was utterly amazed by how fast it was. It packs a little big compared to some others, but if you are boiling water for two, there is nothing faster on the planet. Great review.

Worth a mention that like so many MSR products the stove itself is made in the USA. I’ve used one of these snow camping and it can boil enough snow to make a liter of water in under 5 minutes. Like other isobutane/propane stoves it’s sluggish below about 25 degrees but there are workarounds for that.

Primus fuel. Too bad no Primus stove. Had similar results with the ETA Pots and stove. Feel a little more comfortable putting a larger pot on the ETA setup rather than on the top of a butane bomb. The MSR pot is not such a new idea. Primus ETA pots has been around for how many years now?

Agreed earlier from V. A review is not really regurgitating manufacturer data and calling it all good. Companies fib all the time and get away with it.

I have admired the specs of the MSR since it came out and your great post has confirmed it. However the annoying thing is, and the reason I won’t buy one, they should have designed it to fit any pot. I already own £120 worth of titanium and I’m damned if I’m buying another one. Glad you enjoyed Scotland.

Earlylite, I think it is combination of super efficient, flameless stove, and perfectly nestled so wind free pot. I agree with AlanR, when we first looked at it, we thought -‘they made the same mistake jetboil made. you can’t put a pot on it’ (and before someone comments that you can get an adapter for jetfoil – I know – but it destroys any semblance of fuel efficiency.

My brother in law has one. When we backpack, I have to change my routine a bit when cooking. Usually, I start the water and then start preparing things because I have some time available while the water boils. The MSR is so fast that I pretty much have to have everything else ready because it will be boiling in a heartbeat. It’s one impressive stove.

I own the 1.7L version of this stove and it’s great for bivvying. I leave the burner inside a drybag and the pot / gas sitting outside – right next to my bivvi. When it’s brew time in the morning I just lean over and fire it up. I can have tea and breakfast before even leaving my bivi in the morning.

Hmm just tested a new zealand version of the gnat with an primus heat exchanger pot and 1 liter of 22 dgree C water. Came to a boil in 1 minute 45 secs. Did it again with the same result. Cost of stove? $33 U.S at today’ rates. So no thanks MSR!

I’ve had mine with a 1.7L pot which will fit a 230g/ 8oz cylinder inside. Quick and easy to set up as no wind shield needed, never had a problem with stability, is efficient on fuel with quick cooking times so gas lasts a long time. The 1L pot sounds more ideal for solo use (lighter), the 1.7L is fairly deep to eat from to. They are on the expensive side too. I haven’t had the prob of lid coming unclipped but I normally slip a small piece of sponge and a lighter between gas canister and lid, puts pressure onto clip, maybe stopping it coming undone? I think this review is very fair and agree with it from my own use. Fantastic website too, lots of great gear info. Thanks.